While making modifications to legacy software we have found writes to reserved/undocumented registers. Maybe these are from an early datasheet or errata?
Both writes are to the host PCI configuration space (bus=0, dev=0, fxn=0)
// PCI Bridge Option
0x40 = 0x00000004;
// PCI PIMOSA
0x98 = 0xC0000003;
Does anyone recognize what these register writes are doing?